The invention relates, generally, to Internet protocol (IP) communication systems and, more particularly, to a communication system that uses ATM switches as routers and ATM standards and existing IP protocols to efficiently route IP traffic.
It will be appreciated that the Internet consists of routers owned by Internet Service providers (ISPs) and/or corporate, educational or other information centers (ICs). The routers are connected by lines that are typically leased from telecommunication companies. Because of the phenomenal growth by the Internet in recent years a tremendous burden is presently being placed on the conventional telecommunications infrastructure to handle Internet traffic.
One existing technology designed to carry voice, data and video is asynchronous transfer mode (ATM) technology. Standard ATM technology packs data into cells where each cell is 53 bytes long consisting of a 5 byte header and a 48 byte payload. The packets are transmitted over virtual channels and virtual paths between destination and source end points as will be understood by one skilled in the art. IP traffic using ATM is packet switched such that each router in the network must examine every packet and the router's controller must perform a flow classification on each cell based on the header address. Because the router controller must examine every packet, the flow classification process creates a bottleneck in the flow of packets thereby decreasing the overall efficiency of the network.
In an effort to eliminate this problem, ATM switch protocols that allow the IP packet traffic to "cut-through" the ATM switch such that the packets bypass the controller and travel through the switch at ATM hardware speed have been developed. Examples of such systems are the Ipsilon Networks, Inc. IP Switch, IBM's Aggregate Route-based IP Switching (ARIS) product and Cisco Systems, Inc. tag switching product. While these systems utilize ATM hardware to effectuate the cut-through path, they do not realize the full benefits of ATM routing functionality. For example, these systems use proprietary protocols to set up cut-through paths. As a result, IP traffic cannot be routed between the switches and routers that are based on different proprietary protocols. Some of these systems also require flow classification of the IP traffic where only certain types of traffic are cut-through. One problem with such systems is that the number of flows could outstrip the number of available virtual circuits. Finally, the known systems, although using ATM hardware, do not make use of ATM software and functionality such that the known systems do not provide ATM QOS (quality of service) end to end.
Thus, an improved system for allowing IP traffic to "cut-through" ATM switches is desired.